Window expert, says that pre-existing damage and imperfections are both factors in the doors’ spontaneous shattering, but what else could possibly caused this breakage.

Spontaneous glass breakage is a phenomenon by which toughened glass (or tempered) may spontaneously break without any apparent reason. The most common causes are:

– Minor damage during installation such as nicked or chipped edges later developing into larger breaks normally radiating from point of defect.
– Binding of the glass in the frame, causing stresses to develop as the glass expands and contracts due to thermal changes or deflects due to wind
– Internal defects within the glass such as nickel sulfide inclusions
– Thermal stresses in the glass
– Inadequate glass thickness to resist wind load